My sleep 'schedule' is something like this, in practice. I go to sleep when I'm tired and get up when I wake up and am no longer tired, without worrying about the clock at all, and I've been doing so for 2 years now. My days usually last between 23 and 28 hours, and seem to run longer, not shorter, when I'm stressed or busy, both in terms of the length of time from the start of one sleep to the start of the next and in terms of the awake:asleep ratio.
My friend and I are starting the Uberman sleep schedule (six 20-minute naps spread evenly throughout each day) tonight. Have other lesswrongians experimented with alternate sleep schedules? Are any of you qualified medical experts who can give input or advice? Success stories and failure stories would both be appreciated, and I'll keep you guys posted on our progress.